This invention relates to a novel aqueous agriculturally acceptable herbicidal formulation, a process used to prepare it and a herbicidal method of using it in applying it to weeds or plants to kill and control weeds or plants.
The formulation, preferably a herbicidally efficacious formulation, comprises an effective amount of an agriculturally acceptable salt of N-phosphonomethylglycine and a herbicidally effective amount of at least one agriculturally acceptable fatty acid or a salt thereof or a mixture of fatty acids and a salt(s) thereof or a mixture of salts of a fatty acid(s) giving in an aqueous solution to be applied to plants or a desired locus a pH in a desired range. Other ingredients are optional, including surfactant(s), antifoam(s), antimicrobial(s) or one or more additional pesticides including herbicides, insecticides and fungicides. As used herein, the term xe2x80x9cagriculturally acceptablexe2x80x9d includes residential and industrial uses.
Glyphosate (N-phosphonomethylglycine) well-known as an effective herbicide is an organic acid, and is relatively insoluble in water. Therefore, glyphosate is normally formulated and applied as a water-soluble salt, especially as the isopropylamine salt (IPA salt).
Various formulations of glyphosate are disclosed in U.S. Pat. Nos. 4,405,531 issued to John E. Franz on Sep. 20, 1983; 3,799,580 issued to John E. Franz on Mar. 26, 1974; and 4,840,659 issued to John E. Franz on Jun. 20, 1989. These patents are incorporated herein by reference in their entirety. Roundups herbicide an aqueous concentrate comprising the IPA salt of glyphosate is sold by Monsanto Company as an aqueous concentrate formulation which is normally diluted in water prior to application.
Sharpshooter(TM) Herbicide Concentrate from Safer Inc. is said to contain fatty acid(s) as active ingredients such as those having 8 to 12 carbon atoms and mixtures thereof. It is believed used as a vegetation suppression agent.
SharpShooter(TM) is non-selective, and shows the result of its contact with weeds and unwanted vegetation in the form of necrosis, leaf burn, desiccation, wilting and the like. Typical fatty acids known to produce such symptoms are pelargonic and n-capric acid.
Pelargonic acid referred to also as nonanoic acid, nonylic acid and nonoic acid has the empirical formula C9H18O2.
n-Capric acid known also as n-decanoic acid, has the empirical formula C10H20O2.
PCT/US88/03582 (WO89/03178) of Safer, Inc. discloses a herbicidal composition and method for non-selectively controlling and retarding the growth rate and, if desired, causing extensive mortality of unwanted vegetation. The compositions consist essentially of one or more substances selected from the group consisting of aliphatic acids or their herbicidally active salts, disclosed preferably as octanoic acid, nonanoic acid, decanoic acid, n-decanoic acid, or dodecanoic acid, and an ammonium compound, preferably ammonium nitrate, sulfate or sulfanate. The composition is said to cause a plant mortality significantly in excess of the expected additive mortalities of the individual components.
U.S. Pat. No. 4,975,110 issued to George S. Puritch et al discloses an environmentally compatible herbicidal composition, consisting essentially of a herbicidally effective amount of a saturated linear monocarboxylic fatty acid selected from the group consisting of the acids caprylic, pelargonic, capric, undecanoic, lauric and mixtures thereof; and a surfactant component.
U.S. Pat. No. 3,870,503 issued to Louis G. Nickell on Mar. 11, 1975 discloses that sucrose yield of sugar-cane is increased by treating sugarcane a few weeks prior to harvest with a sugar cane ripening agent selected from the group consisting of n-valeric (pentanoic) acid and alkali metal salts or ethyl esters of an aliphatic monoacid having from one to five carbon atoms.
U.S. Pat. No. 4,134,754 issued to Otto L. Hoffmann on Jan. 16, 1979 discloses that the activity of barban is enhanced and variation of selectivity with climatic conditions is alleviated by applying to wild oats an effective amount of a composition comprising one part by weight carbon and at least four parts by weight of a polyunsaturated fatty acid exemplified by linolenic acid. The composition is preferably either dispersed in water with the aid of an emulsifier or dissolved in a mixture of water and a volatile organic solvent such as acetone.
U.S. Pat. No. 4,436,547 issued to Michael J. Sampson on Mar. 13, 1984 discloses that the effect of fungicides, herbicides, insecticides, nematocides and plant-growth regulators, is improved by co-administration of them with one or more of the following additives: carbohydrates, organic acids (particularly fatty acids and acids of the Krebs tricarboxylic acid cycle), vitamins and co-enzymes, purine and pyrimidine nucleosides and nucleotides, naturally occurring fats and oils, certain amino acids and (but not where the agricultural chemical is itself a plant-growth regulator) plant-growth regulators. The invention is said to provide compositions containing one or more of the said agricultural chemicals and one or more of the said additives and methods of improving the harvest of a given crop by applying to it one or more of the said agricultural chemicals and one or more of the additives, either simultaneously or within up to about ten days of one another.
U.S. Pat. No. 4,626,274 issued to Heinz Hausmann on Dec. 2, 1986 discloses that a known herbicide such as a urea, carboxylic acid ester, aminoacid, benzoic derivative, benzonitrile, phenol derivative, diphenyl ether, triazinone, triazinedione, heterocycle, dipyridil derivative or benzosulphonamide, is rendered more effective by being combined with a synthetic spreading agent such as a silicone oil, etc.
U.S. Pat. No. 4,966,728 issued to James L. Hazen, on Oct. 30, 1990 discloses herbicide adjuvants which are said to enhance the effectiveness of a broad spectrum of postemergent herbicides. These adjuvants preferably contain a low foaming nonionic surfactant, an anionic surfactant, a lower alkanol ester of a fatty acid, and a hydrocarbon oil component.
U.S. Pat. No. 4,902,334 issued to Azuma et al on Feb. 20, 1990 discloses a plant metabolism regulating agent comprising as an active ingredient an alpha, beta or beta, gamma-unsaturated carboxylic acid or its derivative. This concept is said to be useful for controlling the metabolism of a plant, facilitating the growth of a beneficial plant such as cereals by inhibiting the growth of undesirable plants or eradicating them, regulating the growth of a plant and dwarfing a plant.
U.S. Pat. No. 4,904,645 issued to George S. Puritch et al on Feb. 27, 1990 discloses a combination of pyrethrum and fatty acid salt material which is said to provide a stable; commercially useful and environmentally safe pesticidal formulation. The specific composition comprises an aqueous solution having a pH within the range of 7.5 to 8.8; an aqueous solution comprising about 50% by weight of monocarboxylic acids and their alkali metal salts, where the acid mixture is at least 70% oleic acid and 6% linoleic acid; a pyrethrum extract; a solvent for the pyrethrum, which is preferably a 2-6 carbon alcohol; a trace amount of an antioxidant. The composition is said to be effective against insects of at least the orders Homoptera, Coleoptera, Dermaptera, Hemiptera, and Lepidoptera, and against crustacea of the order Isopoda.
An objective of this invention is to provide an aqueous concentrate or ready to apply formulation comprising glyphosate or a water soluble salt of glyphosate and a fatty acid or a salt thereof or a mixture of fatty acids and salt thereof or a mixture of salts of the fatty acid(s) such that the early burndown symptoms on plants of the fatty acid and/or its salt or mixtures thereof are seen and the long term herbicidal control achieved by the use of the glyphosate is maintained and not sacrificed, eliminated or reduced by the contact action of the fatty acid or its water soluble salt. Enhanced shelf-stability is provided when the application pH is in the preferred range.
Without being bound by theory, it is believed that the fatty acid is the responsible moiety for providing the early contact visible symptoms on plants treated with a fatty acid salt contained in a formulation of this invention.
The foregoing objects are provided in an agriculturally acceptable herbicidal composition comprising herbicidally effective amounts of each of:
a) N-phosphonomethylglycine (glyphosate) or an agriculturally acceptable water soluble salt of N-phosphonomethylglycine or a compound which metabolizes thereto and
b) a fatty acid such as a C5 to C16 or preferably a C8 to C12 saturated or unsaturated, straight or branched chain fatty acid or an agriculturally acceptable salt(s) thereof or a mixture of fatty acids and salt(s) thereof or a mixture of salts of a fatty acid(s) recognizing that such fatty acids may themselves be mixtures.
A preferred composition is wherein the ratio of a) to b) is in the range from about 1:10 to about 10:1 by weight and more preferably wherein the ratio of a) to b) is in the range from about 1:5 to about 5:1 and most preferably in the range from about 1:3 to about 3:1.
Especially preferred are the mono-isopropylamine and the trimethylsulfonium salts of N-phosphonomethylglycine.
Especially preferred are the potassium salts of capric fatty acid and pelargonic fatty acid and mixtures thereof. Potassium nonanoate and potassium decanoate may be enployed.
Also disclosed is a method of killing or controlling plants where a herbicidally effective amount of the above described herbicidal composition is applied to said plants to kill or control said plants and wherein the early burndown effect of application of the fatty acid or a salt thereof can be readily seen leaving intact the longer term control opportunity which is provided by simultaneous application of glyphosate or of the glyphosate moiety in the form of a water soluble salt of glyphosate or a compound which metabolizes to glyphosate.
Also disclosed is a process for preparing herbicidal compositions of this invention wherein a base such as those providing hydroxide in water preferably an amine or alkali metal or alkaline earth metal hydroxide most preferably potassium hydroxide is employed to control the desired final adjusted pH in the range from about 6.4 to about 7.25 and preferably in the range from about 6.8 to about 7.0 to provide an improved storage stable formulation, which is ready to use or ready to dilute.
The present invention relates to an agriculturally acceptable herbicidal, shelf-stable ready to use or shelf-stable aqueous concentrate formulation of N-phosphonomethylglycine or a water soluble salt of N-phosphonomethylglycine or salts or mixtures thereof, with one or more C5 to C16 or preferably C8 to C12 saturated or unsaturated, straight or branched chained fatty acid itself or in the form of a salt, salts or various mixtures thereof.
Various optional ingredients may also be employed if desired although not required. Greater or lesser amounts of those optional additiments may be employed as desired.
When the application pH of the formulation of the present invention is in the range from about 6.4 to about 7.25, and more preferably in the range from about 6.8 to about 7.0, the formulations of this invention show increased shelf-stability in that they do not experience separation such as salting out or settling out of one or more ingredients when stored for prolonged periods of time at normal room temperatures or when undergoing accelerated aging studies done at 50xc2x0 C. or 60xc2x0 C. or at freezing temperatures.
As used herein, the phrase xe2x80x9cearly burndown symptomsxe2x80x9d means visible plant symptoms characteristic of the contact action of a fatty acid or a salt thereof upon the leaf of a plant when applied in an effective amount alone to the surface of a plant. Such symptoms illustratively include necrosis, leafburn, desiccation, wilting and the like as visible evidence of herbicidal effectiveness.
As used herein, the term xe2x80x9clong term controlxe2x80x9d means a significant inhibition of regrowth which is achieved through the use of a herbicidally effective amount of glyphosate (or glyphosate salt or a mixture thereof) on a plant to be killed or controlled.
The formulation of the present invention contains at least one water-soluble salt of glyphosate or a mixture of such salts. Several processes for the preparation of glyphosate and its water soluble salts are disclosed in the patent and chemical literature, e.g., U.S. Pat. Nos. 3,977,860 and 4,486,358. Illustrative suitable water-soluble salts of glyphosate useful in the present invention are disclosed in U.S. Pat. No. 4,405,531. The isopropylamine salt of glyphosate is most preferred in the formulation, preparation of the formulation and use of the present invention.
If desired, one or more of ammonium sulfate or potassium sulfate or any other compatible active or compatible nonactive ingredient may be employed as an additional ingredient(s) in a process for preparing a formulation of the present invention, in its preparation and its use.
If ammonium sulfate is used during the formulation process, the formulation is normally filtered (or optional equivalent means) to remove any insoluble particulate materials which may be present in some commercial grades of ammonium sulfate.
The concentrates and solutions of the invention may contain optional additional components, for example anti-freeze agents such as ethylene glycol and propylene glycol.
Other examples are dyes, thickening agents, anti-foam agents, for instance silicone-based anti-foam agents, and surfactants, for instance non-ionic or cationic surfactants.
Additional illustrative suitable nonionic surfactants are recited in U.S. Pat. No. 4,405,531 supra. Other suitable nonionic surfactants will be known to those skilled in the art.
Other surfactants which may be employed include alkylamine oxides, alkyl glucosides, ethoxylated or propoxylated quaternary amines and dialkylacetylene surfactants.
Particularly preferred, although optional, is an ethoxylated tallow amine surfactant having a degree of ethoxylation in the range from about 15 to about 18, mixtures thereof and the like. One such surfactant is Entry II, sold by Monsanto Company, St. Louis, Mo. USA.
The amount of surfactant optionally employed is typically in the range from about 0 to about 2 percent by weight of a ready to use formulation of a spray solution formed by dilution with water of a concentrate formulation of this invention.
The concentrates and ready to use solutions of this invention may also be mixed with other water-soluble herbicides, for example but not limited to, salts of 2,4-dichlorophenoxyacetic acid, dicamba or 4-chloro-2-methylphenoxyacetic acid, or with finely-divided water-insoluble herbicides, for example but not limited to triazines, substituted ureas, sulfonylureas diphenyl ethers, dinitroanilines, pyridines and the like.
While Roundup(copyright) herbicide is the preferred source of a glyphosate water soluble salt, other suitable formulations providing a water soluble glyphosate salt or glyphosate acid may be employed if desired.
Alternatively, the water soluble glyphosate salt or an aqueous solution thereof may be prepared and then added directly as one of the process preparation steps.
Some compositions of the invention were prepared by stirring about a 62 percent by weight aqueous solution of the mono-isopropylamine salt of glyphosate at about room temperature with the desired amount of fatty acid as a potassium salt and optionally, with a saturated solution of ammonium sulfate.
The formulations of the present invention may be conveniently prepared by mixing the desired ingredients together as in a blender or in any suitable container of device producing the needed amount of agitation resulting in mixed ingredients.
Formulation examples were generally prepared by the following process:
(1) adding all or a portion of the desired amount of initial water in a first container,
(2) adding a portion of water and potassium hydroxide to the desired amount of fatty acid in a separate container to form a premix,
(3) adding the fatty acid containing the potassium hydroxide in the premix from the separate container to the first container containing the initial water,
4) adding a water soluble salt of N-phosphonomethylglycine alone with surfactant to the first container to form a desired final non pH adjusted mixture/solution,
5) adjusting the mixture/solution to a final desired pH by adding appropriate amounts of a concentrated potassium hydroxide solution and thereafter if desired,
6) admixing any remaining water and optional ingredients such as an anti-microbial for example Proxel(copyright) GXL (CAS 2634-33-5), sorbic acid, Legend MK, mixtures thereof and the like.
The conversion of a fatty acid such as pelargonic acid to salt such as a potassium salt is the step requiring most scrutiny of the process of this invention.
Pelargonic acid is a thin, clear oil at room temperature which sits on the surface of water when added. With mild agitation, the conversion time to form the salt of the fatty acid is slow. Extreme agitation and long batch stirring time are generally necessary to make the conversion complete which is desired.
In laboratory test batches, preparation of formulations of this invention was generally done by making the fatty acid salt in a separate smaller premix vessel using a beaker and vigorous agitation. This premix was then added to the already mixed ingredients in a larger first container.
As used herein the term xe2x80x9cvigorous agitationxe2x80x9d includes stirring or mixing by any mechanical or equivalent means to produce a well mixed composition providing thorough blending.
The process of preparing a formulation of this invention may be done at temperatures in the range from about 10xc2x0 C. to about 100xc2x0 C. and preferably from about 20xc2x0 C. to about 40xc2x0 C.
As another optional ingredient, an anti-foam agent may be included. Various suitable anti-foam agents include SAG 47 which is preferred as an anti-foam agent and Silicone Anti Foam(copyright) 30 IND.
The amount of anti-foam agent optionally employed is that which is sufficient to control and reduce an amount of foam which may be formed during the process of preparation of the formulation of this invention to a desired satisfactory level from a user""s viewpoint. Generally the concentration of anti-foam agent is in the range from about 0.001% by weight of the total ingredients to about 0.1% although greater or lesser amounts of optional anti-foam agent may be employed.
Alternatively, a premix of about 1 part by weight Roundup(copyright) herbicide, about 2 parts water and potassium hydroxide as a 20 percent by weight solution was used to form a premix. Pelargonic acid was blended in this premix but thereafter separated easily. The benefit of this (alternative) process of preparation was that the premix went into the batch water with only mild agitation. Care must be given to prevent possible heat residue in the premix beaker.
The most preferred previously described process requires some agitation. It may be likely that the addition of the fatty acid at the suction side of a flow through homogenizer Tekmar for example, into the potassium hydroxide composition would be sufficient to produce the desired amount of agitation.
In a preferred process for preparing formulations of this invention, the vessel wherein the formulation will be 50 gallons or more is initially charged with about 25% of the total desired water. Gentle agitation or recirculation is begun during and after this initial water addition. A base providing hydroxide in water is added as is optionally an ethoxylated tallowamine surfactant such as Entry II(copyright) Surfactant, sold by Monsanto Company, St. Louis, Mo. USA.
Agitation is increased and the added fatty acid is allowed to react. When the reaction is considered complete, the fatty acid appears homogeneous and not aggregated at the surface of the resulting composition. About half of the remaining desired water is added as are desired amounts of the isopropylamine salt of glyphosate, and optionally Proxel and Sag 47 with time allowed for adequate mixing. Thereafter remaining desired water is added and the pH is adjusted using potassium hydroxide.
Ready to use formulations having C9 or C10 fatty acids in the range from about 0.5 to about 1% by weight of the total spray weight were the most effective formulations from a herbicidal efficacy viewpoint with mixtures thereof providing similar efficacy.
The formulations of the present invention can be readily used as prepared or further diluted in water by a user in a spray container prior to use, although those of skill in the art will recognize that the dilution will have a practical dilution limit set by efficacy.
Suitable herbicidally efficacious application rates of glyphosate will vary depending on plant species, weather, climate and geography. The spray volume is in the range from about 10 to about 1000 gallons per acre (gpa) preferably from about 50 to about 250 gpa. U.S. Pat. No. 3,799,758 provides illustrative application rates of glyphosate on an acid equivalent basis.
The following examples are presented to illustrate the present invention as well as some of the various embodiments of the invention. These examples are presented as being illustrative of the novel formulations and are not intended to be a limitation of the scope thereof. Rather these examples are intended to teach by illustration and provide what is believed to be a useful and readily understood description of procedures to make and use the invention.
In the examples, all parts, percentages and properties are by weight unless otherwise indicated. In some examples, comparative formulations illustrative of the prior art were made and compared to compositions of this invention.